Reducing occlusion effect in ANR headphones

摘要

In an active noise reducing headphone, a signal processor is configured to apply first feedback filters to the feedback signal path, causing the feedback signal path to operate at a first gain level, as a function of frequency, during a first operating mode, and apply second feedback filters to the feedback signal path, causing the feedback signal path to operate at a second gain level less than the first gain level at some frequencies during a second operating mode. The first gain level is a level of gain that results in effective cancellation of sounds transmitted through or around the ear cup and through the user's head, and the second level is a level of gain that is matched to the level of sound of a typical wearer's voice transmitted through the wearer's head when wearing the headphone.

主权项

1. An active noise reducing headphone comprising:
an ear piece configured to couple to a wearer's ear to define an acoustic volume comprising the volume of air within the wearer's ear canal and a volume within the ear piece; a feedback microphone acoustically coupled to the acoustic volume and electrically coupled to a feedback active noise cancellation signal path; a feed-forward microphone acoustically coupled to an external environment and electrically coupled to a feed-forward active noise cancellation signal path; an output transducer acoustically coupled to the acoustic volume via the first volume and electrically coupled to the feedback signal path and the feed-forward signal path; and a signal processor configured to apply filters and control gains of the feedback signal path and the feed-forward signal path; wherein the signal processor is configured to:
apply first feedback filters to the feedback signal path, the first feedback filters causing the feedback signal path to operate at a first gain level, as a function of frequency, during a first operating mode,apply second feedback filters to the feedback signal path, the second feedback filters causing the feedback signal path to operate at a second gain level less than the first gain level at some frequencies during a second operating mode,apply first feed-forward filters to the feed-forward signal path in conjunction with applying the first feedback filters to the feedback signal path to achieve effective cancellation of ambient sound in the first operating mode, andapply second feed-forward filters to the feed-forward signal path, the second filters being selected to provide active hear-through of ambient sounds with ambient naturalness in the second operating mode; the first gain level being a level of gain that results in effective cancellation of sounds transmitted through or around the ear piece and through the user's head into the acoustic volume when the ear piece is coupled to the wearer's ear, the second level being a level of gain that is matched to the level of sound of a typical wearer's voice transmitted through the wearer's head when the ear piece is coupled to the wearer's ear, and the second feedback filters and the second feed-forward filters are selected to provide active hear-through of a user's own voice with self-naturalness.